Light and lighting . ° 240 1-40 45 153 12-37 0-97 14° 230 1-46 48 162 12-72 0-945 19° 240 140 51 189 13-75 0-874 29° 257 119 54 234 15-30 0-793 37° 30 260 0-88 27 d 468 21-6 0-556 56° 15 200 0-237 30 369 19-2 0,626 51° 20 230 0-391 33 j 288 170 0-707 45° 252 0-61!i 36 225 150 0-80 36° 50 260 0-925 39 180 13-42 0-895 26° 30 250 1-245 42 153 12-37 0-97 14° 230 L-455 45 144 120 1 0 215 L-492 48 153 12-37 0-97 14° 230 1 155 51 180 13-42 0-895 26° 30 250 1-245 54 225 15-0 0-80 36° 50 260 0-925 102 THE ELLUMINATIXG ENGINEER ai-rii.) such a calculation, the table for LampIII. is given, and the final
Light and lighting . ° 240 1-40 45 153 12-37 0-97 14° 230 1-46 48 162 12-72 0-945 19° 240 140 51 189 13-75 0-874 29° 257 119 54 234 15-30 0-793 37° 30 260 0-88 27 d 468 21-6 0-556 56° 15 200 0-237 30 369 19-2 0,626 51° 20 230 0-391 33 j 288 170 0-707 45° 252 0-61!i 36 225 150 0-80 36° 50 260 0-925 39 180 13-42 0-895 26° 30 250 1-245 42 153 12-37 0-97 14° 230 L-455 45 144 120 1 0 215 L-492 48 153 12-37 0-97 14° 230 1 155 51 180 13-42 0-895 26° 30 250 1-245 54 225 15-0 0-80 36° 50 260 0-925 102 THE ELLUMINATIXG ENGINEER ai-rii.) such a calculation, the table for LampIII. is given, and the final table for thelong centre line of the room, Bhowingthemethod of collecting values together. In all these tables, h vertical ln-i^htof lamp above reference plane, 0 angle The mean of all the calculated valuesof the horizontal illumination is 2 foot-candles almosl exactly. In deducingtliis tin- -1;»ti 1111- along the boundary oftin- area were weighted to only hall thevalue f those in the centre. This com-. l Workshop lighted by tungsten lamps in metal reflectors horizontal illumination from vertical f line joining lamp with[MPint considered, and 1 intensity incandle-power in this direction read offfrom the polar curve. The horizontal illumination in the last column is calcu-lated from the << I < ? (total distance)1an expression equivalent to I . I. and 6 give calculated andobserved illumination curves, the < ?of tin- observed values l»in«_r due t<. tin- additional litam>il l>v reflection from the walls. There is no flux above78 . and the reflection from the roof isnegligible. pares with 2*5 foot-candles, tin- av<of the observations, giving a gain f 0*5foot-candle or 25 percent, due to 1 <•(!<?< ti<<nfrom tin- walls. Tin lighting f this room was nextexamined by considering tin- total fluxwhich reaches the pl
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